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<h1>Penlight</h1>

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<h2>Contents</h2>
<ul>
<li><a href="#Methods">Methods</a></li>
<li><a href="#Metamethods">Metamethods</a></li>
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<h2>Classes</h2>
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  <li><strong>pl.Set</strong></li>
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<h1>Class <code>pl.Set</code></h1>
<p>A Set class.</p>
<p>



<pre>
&gt; Set = <span class="global">require</span> <span class="string">'pl.Set'</span>
&gt; = Set{<span class="string">'one'</span>,<span class="string">'two'</span>} == Set{<span class="string">'two'</span>,<span class="string">'one'</span>}
<span class="keyword">true</span>
&gt; fruit = Set{<span class="string">'apple'</span>,<span class="string">'banana'</span>,<span class="string">'orange'</span>}
&gt; = fruit[<span class="string">'banana'</span>]
<span class="keyword">true</span>
&gt; = fruit[<span class="string">'hazelnut'</span>]
<span class="keyword">nil</span>
&gt; colours = Set{<span class="string">'red'</span>,<span class="string">'orange'</span>,<span class="string">'green'</span>,<span class="string">'blue'</span>}
&gt; = fruit,colours
[apple,orange,banana]   [blue,green,orange,red]
&gt; = fruit+colours
[blue,green,apple,red,orange,banana]
[orange]
&gt; more_fruits = fruit + <span class="string">'apricot'</span>
&gt; = fruit*colours
 =  more_fruits, fruit
banana,apricot,apple,orange]    [banana,apple,orange]
</pre>

<p> Dependencies: <a href="../libraries/pl.utils.html#">pl.utils</a>, <a href="../libraries/pl.tablex.html#">pl.tablex</a>, <a href="../libraries/pl.class.html#">pl.class</a>, <a href="../classes/pl.Map.html#">pl.Map</a>, (<a href="../classes/pl.List.html#">pl.List</a> if __tostring is used)</p>
</p>


<h2><a href="#Methods">Methods</a></h2>
<table class="function_list">
	<tr>
	<td class="name" nowrap><a href="#pl.Set:Set">pl.Set:Set (t)</a></td>
	<td class="summary">create a set.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:values">pl.Set:values (self)</a></td>
	<td class="summary">get a list of the values in a set.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:map">pl.Set:map (self, fn, ...)</a></td>
	<td class="summary">map a function over the values of a set.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:union">pl.Set:union (self, set)</a></td>
	<td class="summary">union of two sets (also +).</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:intersection">pl.Set:intersection (self, set)</a></td>
	<td class="summary">intersection of two sets (also *).</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:difference">pl.Set:difference (self, set)</a></td>
	<td class="summary">new set with elements in the set that are not in the other (also -).</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:issubset">pl.Set:issubset (self, set)</a></td>
	<td class="summary">is the first set a subset of the second (also &lt;)?.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:isempty">pl.Set:isempty (self)</a></td>
	<td class="summary">is the set empty?.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:isdisjoint">pl.Set:isdisjoint (s1, s2)</a></td>
	<td class="summary">are the sets disjoint?</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:len">pl.Set:len (s)</a></td>
	<td class="summary">size of this set (also # for 5.2).</td>
	</tr>
</table>
<h2><a href="#Metamethods">Metamethods</a></h2>
<table class="function_list">
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__tostring">pl.Set:__tostring ()</a></td>
	<td class="summary">string representation of a set.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__add">pl.Set:__add ()</a></td>
	<td class="summary">union of sets.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__mul">pl.Set:__mul ()</a></td>
	<td class="summary">intersection of sets.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__sub">pl.Set:__sub ()</a></td>
	<td class="summary">difference of sets.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__pow">pl.Set:__pow ()</a></td>
	<td class="summary">symmetric difference of sets.</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__lt">pl.Set:__lt ()</a></td>
	<td class="summary">first set subset of second?</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__len">pl.Set:__len ()</a></td>
	<td class="summary">cardinality of set (5.2).</td>
	</tr>
	<tr>
	<td class="name" nowrap><a href="#pl.Set:__eq">pl.Set:__eq (s1, s2)</a></td>
	<td class="summary">equality between sets.</td>
	</tr>
</table>

<br/>
<br/>


    <h2 class="section-header "><a name="Methods"></a>Methods</h2>

    <dl class="function">
    <dt>
    <a name = "pl.Set:Set"></a>
    <strong>pl.Set:Set (t)</strong>
    </dt>
    <dd>
    create a set.  <br>


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">t</span>
         may be a Set, Map or list-like table.
        </li>
    </ul>





</dd>
    <dt>
    <a name = "pl.Set:values"></a>
    <strong>pl.Set:values (self)</strong>
    </dt>
    <dd>
    get a list of the values in a set.


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        a list
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:map"></a>
    <strong>pl.Set:map (self, fn, ...)</strong>
    </dt>
    <dd>
    map a function over the values of a set.


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
        <li><span class="parameter">fn</span>
         a function
        </li>
        <li><span class="parameter">...</span>
         extra arguments to pass to the function.
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        a new set
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:union"></a>
    <strong>pl.Set:union (self, set)</strong>
    </dt>
    <dd>
    union of two sets (also +).


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
        <li><span class="parameter">set</span>
         another set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        a new set
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:intersection"></a>
    <strong>pl.Set:intersection (self, set)</strong>
    </dt>
    <dd>
    intersection of two sets (also *).


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
        <li><span class="parameter">set</span>
         another set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        a new set
    </ol>



    <h3>Usage:</h3>
    <ul>
        <pre class="example">&gt; s = Set{<span class="number">10</span>,<span class="number">20</span>,<span class="number">30</span>}
&gt; t = Set{<span class="number">20</span>,<span class="number">30</span>,<span class="number">40</span>}
&gt; = t
[<span class="number">20</span>,<span class="number">30</span>,<span class="number">40</span>]
&gt; = Set.intersection(s,t)
[<span class="number">30</span>,<span class="number">20</span>]
&gt; = s*t
[<span class="number">30</span>,<span class="number">20</span>]</pre>
    </ul>

</dd>
    <dt>
    <a name = "pl.Set:difference"></a>
    <strong>pl.Set:difference (self, set)</strong>
    </dt>
    <dd>
    new set with elements in the set that are not in the other (also -).


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
        <li><span class="parameter">set</span>
         another set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        a new set
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:issubset"></a>
    <strong>pl.Set:issubset (self, set)</strong>
    </dt>
    <dd>
    is the first set a subset of the second (also &lt;)?.


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
        <li><span class="parameter">set</span>
         another set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        true or false
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:isempty"></a>
    <strong>pl.Set:isempty (self)</strong>
    </dt>
    <dd>
    is the set empty?.


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">self</span>
         a Set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        true or false
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:isdisjoint"></a>
    <strong>pl.Set:isdisjoint (s1, s2)</strong>
    </dt>
    <dd>
    are the sets disjoint?  (no elements in common).
 Uses naive definition, i.e. that intersection is empty


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">s1</span>
         a Set
        </li>
        <li><span class="parameter">s2</span>
         another set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        true or false
    </ol>




</dd>
    <dt>
    <a name = "pl.Set:len"></a>
    <strong>pl.Set:len (s)</strong>
    </dt>
    <dd>
    size of this set (also # for 5.2).


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">s</span>
         a Set
        </li>
    </ul>

    <h3>Returns:</h3>
    <ol>

        size
    </ol>




</dd>
</dl>
    <h2 class="section-header "><a name="Metamethods"></a>Metamethods</h2>

    <dl class="function">
    <dt>
    <a name = "pl.Set:__tostring"></a>
    <strong>pl.Set:__tostring ()</strong>
    </dt>
    <dd>
    string representation of a set.







</dd>
    <dt>
    <a name = "pl.Set:__add"></a>
    <strong>pl.Set:__add ()</strong>
    </dt>
    <dd>
    union of sets.







</dd>
    <dt>
    <a name = "pl.Set:__mul"></a>
    <strong>pl.Set:__mul ()</strong>
    </dt>
    <dd>
    intersection of sets.







</dd>
    <dt>
    <a name = "pl.Set:__sub"></a>
    <strong>pl.Set:__sub ()</strong>
    </dt>
    <dd>
    difference of sets.







</dd>
    <dt>
    <a name = "pl.Set:__pow"></a>
    <strong>pl.Set:__pow ()</strong>
    </dt>
    <dd>
    symmetric difference of sets.







</dd>
    <dt>
    <a name = "pl.Set:__lt"></a>
    <strong>pl.Set:__lt ()</strong>
    </dt>
    <dd>
    first set subset of second?







</dd>
    <dt>
    <a name = "pl.Set:__len"></a>
    <strong>pl.Set:__len ()</strong>
    </dt>
    <dd>
    cardinality of set (5.2).







</dd>
    <dt>
    <a name = "pl.Set:__eq"></a>
    <strong>pl.Set:__eq (s1, s2)</strong>
    </dt>
    <dd>
    equality between sets.


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">s1</span>



        </li>
        <li><span class="parameter">s2</span>



        </li>
    </ul>





</dd>
</dl>


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